U.S. patent application number 11/929161 was filed with the patent office on 2009-04-30 for fluid ejection device.
Invention is credited to Tony S. Cruz-Uribe, Adel Jilani, Hui Liu, David Pidwerbecki, Jun Zeng.
Application Number | 20090109262 11/929161 |
Document ID | / |
Family ID | 40582292 |
Filed Date | 2009-04-30 |
United States Patent
Application |
20090109262 |
Kind Code |
A1 |
Cruz-Uribe; Tony S. ; et
al. |
April 30, 2009 |
FLUID EJECTION DEVICE
Abstract
A fluid ejection device includes a fluid chamber having a first
sidewall and a second sidewall, a flexible membrane extended over
the fluid chamber and supported at an end of the first sidewall and
an end of the second sidewall, an actuator provided on the flexible
membrane, a first gap provided between the flexible membrane and
the end of the first sidewall, and a second gap provided between
the flexible membrane and the end of the second sidewall, and
compliant material provided within the first gap and within the
second gap. As such, the actuator is adapted to deflect the
flexible membrane relative to the fluid chamber.
Inventors: |
Cruz-Uribe; Tony S.;
(Corvallis, OR) ; Jilani; Adel; (Corvallis,
OR) ; Pidwerbecki; David; (Corvallis, OR) ;
Zeng; Jun; (Corvallis, OR) ; Liu; Hui;
(Corvallis, OR) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD, INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Family ID: |
40582292 |
Appl. No.: |
11/929161 |
Filed: |
October 30, 2007 |
Current U.S.
Class: |
347/68 |
Current CPC
Class: |
B41J 2/14233
20130101 |
Class at
Publication: |
347/68 |
International
Class: |
B41J 2/04 20060101
B41J002/04; B21D 53/76 20060101 B21D053/76; B41J 2/045 20060101
B41J002/045; B23P 17/00 20060101 B23P017/00 |
Claims
1. A fluid ejection device, comprising: a fluid chamber having a
first sidewall and a second sidewall; a flexible membrane extended
over the fluid chamber and supported at an end of the first
sidewall and an end of the second sidewall; an actuator provided on
the flexible membrane, the actuator adapted to deflect the flexible
membrane relative to the fluid chamber; a first gap provided
between the flexible membrane and the end of the first sidewall,
and a second gap provided between the flexible membrane and the end
of the second sidewall; and compliant material provided within the
first gap and within the second gap.
2. The fluid ejection device of claim 1, further comprising: a
first support extended from one of the flexible membrane and the
end of the first sidewall, and a second support extended from one
of the flexible membrane and the end of the second sidewall,
wherein the flexible membrane is supported at the end of the first
sidewall by the first support and at the end of the second sidewall
by the second support, and wherein the first gap is provided
between the flexible membrane and the end of the first sidewall
adjacent the first support, and the second gap is provided between
the flexible membrane and the end of the second sidewall adjacent
the second support.
3. The fluid ejection device of claim 2, further comprising: a
first cavity provided between the first support and the compliant
material within the first gap, and a second cavity provided between
the second support and the compliant material within the second
gap.
4. The fluid ejection device of claim 1, wherein the first sidewall
and the second sidewall each have a width, and wherein the first
gap and the second gap each have a width less than the width of the
first sidewall and the second sidewall, respectively.
5. The fluid ejection device of claim 4, wherein a width of the
compliant material within the first gap and within the second gap
is substantially equal to the width of the first gap and the second
gap, respectively.
6. The fluid ejection device of claim 4, wherein a width of the
compliant material within the first gap and within the second gap
is less than the width of the first gap and the second gap,
respectively.
7. The fluid ejection device of claim 1, wherein the first gap and
the second gap each have a depth, and wherein a thickness of the
compliant material within the first gap and within the second gap
is substantially equal to the depth of the first gap and the second
gap, respectively.
8. The fluid ejection device of claim 1, wherein a width of
displacement of the flexible membrane is greater than a width of
the fluid chamber.
9. The fluid ejection device of claim 1, wherein the fluid chamber
includes an array of fluid chambers having respective first
sidewalls and respective second sidewalls, wherein the flexible
membrane includes flexible membrane portions each extended over one
of the fluid chambers and supported at an end of the respective
first sidewalls and an end of the respective second sidewalls,
wherein the actuator includes a plurality of actuators each
provided on a respective flexible membrane portion, wherein
respective first gaps are provided between the respective flexible
membrane portions and the end of the respective first sidewalls,
and respective second gaps are provided between the respective
flexible membrane portions and the end of the respective second
sidewalls, and wherein the compliant material is provided within
the respective first gaps and within the respective second
gaps.
10. A fluid ejection device, comprising: a fluid chamber having a
first sidewall and a second sidewall; means for supporting a
flexible membrane extended over the fluid chamber by the first
sidewall and the second sidewall, and providing a first gap between
the flexible membrane and an end of the first sidewall and a second
gap between the flexible membrane and an end of the second
sidewall; means for deflecting the flexible membrane relative to
the fluid chamber; and compliant material provided within the first
gap and within the second gap.
11. The fluid ejection device of claim 10, wherein the means for
supporting the flexible membrane and providing the first gap and
the second gap includes a first support extended from one of the
flexible membrane and the end of the first sidewall, and a second
support extended from one of the flexible membrane and the end of
the second sidewall, wherein the first gap is provided between the
flexible membrane and the end of the first sidewall adjacent the
first support, and the second gap is provided between the flexible
membrane and the end of the second sidewall adjacent the second
support.
12. The fluid ejection device of claim 10, further comprising:
means for providing a first cavity between the means for supporting
the flexible membrane and the compliant material within the first
gap, and a second cavity between the means for supporting the
flexible membrane and the compliant material within the second
gap.
13. The fluid ejection device of claim 10, wherein the first
sidewall and the second sidewall each have a width, and wherein the
first gap and the second gap each have a width less than the width
of the first sidewall and the second sidewall, respectively.
14. The fluid ejection device of claim 13, wherein a width of the
compliant material within the first gap and within the second gap
is substantially equal to the width of the first gap and the second
gap, respectively.
15. The fluid ejection device of claim 13, wherein a width of the
compliant material within the first gap and within the second gap
is less than the width of the first gap and the second gap,
respectively.
16. The fluid ejection device of claim 10, wherein the first gap
and the second gap each have a depth, and wherein a thickness of
the compliant material within the first gap and within the second
gap is substantially equal to the depth of the first gap and the
second gap, respectively.
17. A method of forming a fluid ejection device, comprising:
forming a fluid chamber with a first sidewall and a second
sidewall; extending a flexible membrane over the fluid chamber and
supporting the flexible membrane at an end of the first sidewall
and an end of the second sidewall, including providing a first gap
between the flexible membrane and the end of the first sidewall,
and providing a second gap between the flexible membrane and the
end of the second sidewall; providing an actuator on the flexible
membrane, wherein the actuator is adapted to deflect the flexible
membrane relative to the fluid chamber; and providing compliant
material within the first gap and within the second gap.
18. The method of claim 17, further comprising: extending a first
support from one of the flexible membrane and the end of the first
sidewall, and extending a second support from one of the flexible
membrane and the end of the second sidewall, wherein supporting the
flexible membrane includes supporting the flexible membrane at the
end of the first sidewall by the first support, and supporting the
flexible membrane at the end of the second sidewall by the second
support, and wherein providing the first gap and providing the
second gap includes providing the first gap between the flexible
membrane and the end of the first sidewall adjacent the first
support, and providing the second gap between the flexible membrane
and the end of the second sidewall adjacent the second support.
19. The method of claim 18, further comprising: providing a first
cavity between the first support and the compliant material within
the first gap, and providing a second cavity between the second
support and the compliant material within the second gap.
20. The method of claim 17, wherein the first sidewall and the
second sidewall each have a width, and wherein providing the first
gap and providing the second gap includes providing the first gap
and the second gap each with a width less than the width of the
first sidewall and the second sidewall, respectively.
21. The method of claim 20, wherein providing the compliant
material within the first gap and within the second gap includes
providing the compliant material with a width substantially equal
to the width of the first gap and the second gap, respectively.
22. The method of claim 20, wherein providing the compliant
material within the first gap and within the second gap includes
providing the compliant material with a width less than the width
of the first gap and the second gap, respectively.
23. The method of claim 17, wherein providing the compliant
material within the first gap and within the second gap includes
providing the compliant material with a thickness substantially
equal to a depth of the first gap and the second gap, respectively.
Description
BACKGROUND
[0001] An inkjet printing system, as one embodiment of a fluid
ejection system, may include a printhead, an ink supply which
supplies liquid ink to the printhead, and an electronic controller
which controls the printhead. The printhead, as one embodiment of a
fluid ejection device, ejects drops of ink through a plurality of
nozzles or orifices and toward a print medium, such as a sheet of
paper, so as to print onto the print medium. Typically, the
orifices are arranged in one or more columns or arrays such that
properly sequenced ejection of ink from the orifices causes
characters or other images to be printed upon the print medium as
the printhead and the print medium are moved relative to each
other.
[0002] One type of printhead includes a piezoelectrically actuated
printhead. The piezoelectrically actuated printhead includes a
substrate defining a fluid chamber, a flexible membrane supported
by the substrate over the fluid chamber, and an actuator provided
on the flexible membrane. In one arrangement, the actuator includes
a piezoelectric material which deforms when an electrical voltage
is applied. As such, when the piezoelectric material deforms, the
flexible membrane deflects thereby causing ejection of fluid from
the fluid chamber and through an orifice or nozzle communicated
with the fluid chamber.
[0003] One way to increase orifice or nozzle density or pitch is by
reducing a width or distance between sidewalls of the fluid
chamber. Reducing the width or distance between sidewalls of the
fluid chamber, however, narrows the support for the flexible
membrane thereby demanding an increased drive voltage for the
actuator due to the greater stiffness of the flexible membrane.
Thus, to operate the actuator with the same drive voltage, the
flexible membrane is often made thinner. Making the flexible
membrane thinner, however, increases strain on the flexible
membrane near the sidewalls of the fluid chamber. For these and
other reasons, there is a need for the present invention.
SUMMARY
[0004] One aspect of the present invention provides a fluid
ejection device. The fluid ejection device includes a fluid chamber
having a first sidewall and a second sidewall, a flexible membrane
extended over the fluid chamber and supported at an end of the
first sidewall and an end of the second sidewall, an actuator
provided on the flexible membrane, a first gap provided between the
flexible membrane and the end of the first sidewall, and a second
gap provided between the flexible membrane and the end of the
second sidewall, and compliant material provided within the first
gap and within the second gap. As such, the actuator is adapted to
deflect the flexible membrane relative to the fluid chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a block diagram illustrating one embodiment of an
inkjet printing system according to the present invention.
[0006] FIG. 2 is a schematic cross-sectional view illustrating one
embodiment of a portion of a printhead assembly according to the
present invention.
[0007] FIG. 3 is a schematic cross-sectional view illustrating
another embodiment of a portion of a printhead assembly according
to the present invention.
[0008] FIG. 4 is a schematic cross-sectional view illustrating
another embodiment of a portion of a printhead assembly according
to the present invention.
DETAILED DESCRIPTION
[0009] In the following detailed description, reference is made to
the accompanying drawings which form a part hereof, and in which is
shown by way of illustration specific embodiments in which the
invention may be practiced. In this regard, directional
terminology, such as "top," "bottom," "front," "back," "leading,"
"trailing," etc., is used with reference to the orientation of the
Figure(s) being described. Because components of embodiments of the
present invention can be positioned in a number of different
orientations, the directional terminology is used for purposes of
illustration and is in no way limiting. It is to be understood that
other embodiments may be utilized and structural or logical changes
may be made without departing from the scope of the present
invention. The following detailed description, therefore, is not to
be taken in a limiting sense, and the scope of the present
invention is defined by the appended claims.
[0010] FIG. 1 illustrates one embodiment of an inkjet printing
system 10 according to the present invention. Inkjet printing
system 10 constitutes one embodiment of a fluid ejection system
which includes a fluid ejection device, such as a printhead
assembly 12, and a fluid supply, such as an ink supply assembly 14.
In the illustrated embodiment, inkjet printing system 10 also
includes a mounting assembly 16, a media transport assembly 18, and
an electronic controller 20.
[0011] Printhead assembly 12, as one embodiment of a fluid ejection
device, is formed according to an embodiment of the present
invention and ejects drops of ink, including one or more colored
inks, through a plurality of orifices or nozzles 13. While the
following description refers to the ejection of ink from printhead
assembly 12, it is understood that other liquids, fluids, or
flowable materials may be ejected from printhead assembly 12.
[0012] In one embodiment, the drops are directed toward a medium,
such as print medium 19, so as to print onto print medium 19.
Typically, nozzles 13 are arranged in one or more columns or arrays
such that properly sequenced ejection of ink from nozzles 13
causes, in one embodiment, characters, symbols, and/or other
graphics or images to be printed upon print medium 19 as printhead
assembly 12 and print medium 19 are moved relative to each
other.
[0013] Print medium 19 includes, for example, paper, card stock,
envelopes, labels, transparent film, cardboard, rigid panels, and
the like. In one embodiment, print medium 19 is a continuous form
or continuous web print medium 19. As such, print medium 19 may
include a continuous roll of unprinted paper.
[0014] Ink supply assembly 14, as one embodiment of a fluid supply,
supplies ink to printhead assembly 12 and includes a reservoir 15
for storing ink. As such, ink flows from reservoir 15 to printhead
assembly 12. In one embodiment, ink supply assembly 14 and
printhead assembly 12 form a recirculating ink delivery system. As
such, ink flows back to reservoir 15 from printhead assembly 12. In
one embodiment, printhead assembly 12 and ink supply assembly 14
are housed together in an inkjet or fluidjet cartridge or pen. In
another embodiment, ink supply assembly 14 is separate from
printhead assembly 12 and supplies ink to printhead assembly 12
through an interface connection, such as a supply tube (not
shown).
[0015] Mounting assembly 16 positions printhead assembly 12
relative to media transport assembly 18, and media transport
assembly 18 positions print medium 19 relative to printhead
assembly 12. As such, a print zone 17 within which printhead
assembly 12 deposits ink drops is defined adjacent to nozzles 13 in
an area between printhead assembly 12 and print medium 19. Print
medium 19 is advanced through print zone 17 during printing by
media transport assembly 18.
[0016] In one embodiment, printhead assembly 12 is a scanning type
printhead assembly, and mounting assembly 16 moves printhead
assembly 12 relative to media transport assembly 18 and print
medium 19 during printing of a swath on print medium 19. In another
embodiment, printhead assembly 12 is a non-scanning type printhead
assembly, and mounting assembly 16 fixes printhead assembly 12 at a
prescribed position relative to media transport assembly 18 during
printing of a swath on print medium 19 as media transport assembly
18 advances print medium 19 past the prescribed position.
[0017] Electronic controller 20 communicates with printhead
assembly 12, mounting assembly 16, and media transport assembly 18.
Electronic controller 20 receives data 21 from a host system, such
as a computer, and includes memory for temporarily storing data 21.
Typically, data 21 is sent to inkjet printing system 10 along an
electronic, infrared, optical or other information transfer path.
Data 21 represents, for example, a document and/or file to be
printed. As such, data 21 forms a print job for inkjet printing
system 10 and includes one or more print job commands and/or
command parameters.
[0018] In one embodiment, electronic controller 20 provides control
of printhead assembly 12 including timing control for ejection of
ink drops from nozzles 13. As such, electronic controller 20
defines a pattern of ejected ink drops which form characters,
symbols, and/or other graphics or images on print medium 19. Timing
control and, therefore, the pattern of ejected ink drops, is
determined by the print job commands and/or command parameters. In
one embodiment, logic and drive circuitry forming a portion of
electronic controller 20 is located on printhead assembly 12. In
another embodiment, logic and drive circuitry forming a portion of
electronic controller 20 is located off printhead assembly 12.
[0019] FIG. 2 illustrates one embodiment of a portion of printhead
assembly 12. Printhead assembly 12, as one embodiment of a fluid
injection device, includes a substrate 120, a flexible membrane
130, and actuators 140. Substrate 120, flexible membrane 130, and
actuators 140 are arranged and interact, as described below, to
eject drops of fluid from printhead assembly 12.
[0020] In one embodiment, substrate 120 has a plurality of fluid
chambers 122 defined therein. In one embodiment, fluid chambers 122
are defined by sidewalls 124 of substrate 120. Fluid chambers 122
communicate with a supply of fluid such that fluid within fluid
chamber 122 is ejected from fluid chambers 122 through orifices or
nozzles 13 (FIG. 1) communicated with fluid chambers 122. In one
embodiment, fluid within fluid chambers 122 is ejected in a
direction substantially perpendicular to a direction of
displacement or deflection of flexible membrane 130 (for example,
in a direction into or out of the plane of FIG. 2).
[0021] In one embodiment, substrate 120 is a silicon substrate and
fluid chambers 122 are formed in substrate 120 using
photolithography and etching techniques.
[0022] As illustrated in the embodiment of FIG. 2, flexible
membrane 130 is supported by substrate 120 and extends over fluid
chambers 122. More specifically, in one embodiment, flexible
membrane 130 is supported by sidewalls 124 of substrate 120. In one
embodiment, flexible membrane 130 is a single membrane extended
over an array of or multiple fluid chambers 122. As such, in one
embodiment, flexible membrane 130 includes flexible membrane
portions 132 each defined over one fluid chamber 122.
[0023] In one embodiment, flexible membrane 130 is formed of a
flexible material such as, for example, a flexible thin film of
silicon nitride or silicon carbide, or a flexible thin layer of
silicon. In one exemplary embodiment, flexible membrane 130 is
formed of glass. In one embodiment, flexible membrane 130 is
attached to substrate 120 by anodic bonding or similar
techniques.
[0024] As illustrated in the embodiment to FIG. 2, actuators 140
are provided on flexible membrane 130. More specifically, each
actuator 140 is provided on a respective flexible membrane portion
132. In one embodiment, as described below, actuators 140 deflect
flexible membrane portions 132 such that when flexible membrane
portions 132 of flexible membrane 130 deflect, droplets of fluid
are ejected from a respective orifice or nozzle 13 (FIG. 1) of
printhead assembly 12.
[0025] In one embodiment, actuators 140 are provided or formed on a
side of flexible membrane 130 opposite fluid chambers 122. As such,
actuators 140 are not in direct contact with fluid contained within
fluid chambers 122. Thus, potential affects of fluid contacting
actuators 140, such as corrosion or electrical shorting, are
reduced.
[0026] In one embodiment, actuators 140 include a piezoelectric
material which changes shape, for example, expands and/or
contracts, in response to an electrical signal. Thus, in response
to the electrical signal, actuators 140 apply a force to respective
flexible membrane portions 132 which cause flexible membrane
portions 132 to deflect. Examples of a piezoelectric material
include zinc oxide or a piezoceramic material such as barium
titanate, lead zirconium titanate (PZT), or lead lanthanum
zirconium titanate (PLZT). It is understood that actuators 140 may
include any type of device which causes movement or deflection of
flexible membrane portions 132 including, for example, an
electrostatic, magnetostatic, and/or thermal expansion
actuator.
[0027] In one embodiment, actuators 140 are formed from a single or
common piezoelectric material. More specifically, the single or
common piezoelectric material is provided on flexible membrane 130,
and selective portions of the piezoelectric material are removed
such that the remaining portions of the piezoelectric material
define actuators 140.
[0028] As illustrated in the embodiment of FIG. 2, flexible
membrane 130 is supported at ends 126 of sidewalls 124. In one
embodiment, flexible membrane 130 is supported at ends 126 such
that gaps 150 are provided between flexible membrane 130 and ends
126 of sidewalls 124. In one embodiment, gaps 150 are formed by
posts or supports 128 extended from ends 126 of sidewalls 124. As
such, flexible membrane 130 is supported at ends 126 of sidewalls
124 by supports 128.
[0029] Although a single post or support 128 is illustrated as
extending from a respective end 126 of each sidewall 124, it is
within the scope of the present invention for one or more posts or
supports 128 to extend from a respective end 126 of each sidewall
124. In addition, although posts or supports 128 are illustrated as
extending from a center of sidewalls 124, it is within the scope of
the present invention for posts or supports 128 to be offset from a
center of a respective sidewall 124.
[0030] In one embodiment, sidewalls 124 have a width W and supports
128 have a height H. In addition, gaps 150 have a width w and a
depth d. In one embodiment, width w of gaps 150 is less than width
W of sidewalls 124, and depth d of gaps 150 is equal to or
corresponds to height H of supports 128. In one embodiment, height
H of supports 128 and, therefore, depth d of gaps 150 is less than
100.times. a maximum distance of displacement or deflection of
flexible membrane 130. In one exemplary embodiment, for example, a
maximum distance of displacement or deflection of flexible membrane
130 is approximately 0.1 microns. Thus, in one exemplary
embodiment, height H of supports 128 and, therefore, depth d of
gaps 150 is less than approximately 10 microns.
[0031] By supporting flexible membrane 130 by supports 128 and
providing gaps 150 between flexible membrane 130 and ends 126 of
sidewalls 124, a supported width of flexible membrane 130, referred
to herein as the effective width (W.sub.EFF) of flexible membrane
130, is increased relative to a width (W.sub.FC) of fluid chambers
122 as defined between sidewalls 124. For example, the effective
width of flexible membrane 130 is increased by 2.times. width w of
gaps 150. By increasing the effective width of flexible membrane
130, displacement of flexible membrane 130 may also be increased.
As such, a desired displacement of flexible membrane 130 may be
achieved with a reduced or narrower distance between sidewalls 124.
Accordingly, fluid chambers 122, and their associated orifices or
nozzles, may be positioned closer together thereby enabling higher
orifice or nozzle density. In addition, width W of sidewalls 124
may be maintained thereby minimizing or avoiding mechanical
cross-talk between adjacent fluid chambers 122.
[0032] In one embodiment, as illustrated in FIG. 2, compliant
material 160 is provided within gaps 150. As such, compliant
material 160 seals gaps 150 while still allowing flexible membrane
130 to move or deflect. By sealing gaps 150, compliant material 160
prevents bubbles or particles in fluid within fluid chambers 122
from being trapped in gaps 150. In addition, compliant material 160
may act as a dampener to quell high frequency modes of flexible
membrane 130. In one exemplary embodiment, compliant material 160
is a polymer material such as parylene, ORDYL.RTM. or SU8.RTM..
[0033] As illustrated in the embodiment of FIG. 2, compliant
material 160 has a thickness T and a length L. In one embodiment,
thickness T of compliant material 160 is substantially equal to or
substantially corresponds to height H of supports 128. As depth d
of gaps 150 corresponds to height H of supports 128, compliant
material 160 substantially fills and seals depth d of gaps 150. In
one embodiment, length L of compliant material 160 is substantially
equal to or substantially corresponds to width w of gaps 150. As
such, compliant material 160 substantially fills and seals width w
of gaps 150.
[0034] In one exemplary embodiment, compliant material 160 is
formed by a polymer coating, such as parylene, vapor deposited to
fill gaps 150. In one exemplary embodiment, with a width of fluid
chambers 122 being approximately 410 microns, width W of sidewalls
124 being approximately 100 microns, a thickness of flexible
membrane 130 being approximately 50 microns, and a thickness of
actuators 140 being approximately 45 microns, thickness T of
compliant material 160 is in a range of approximately 5 microns to
approximately 10 microns, and length L of compliant material 160 is
approximately 37 microns.
[0035] FIG. 3 illustrates another embodiment of printhead assembly
12. In the embodiment of FIG. 3, printhead assembly 12' includes
substrate 120, flexible membrane 130, and actuators 140. In
addition, printhead assembly 12' includes gaps 150 provided between
flexible membranes 130 and ends 126 of sidewalls 124. As
illustrated and described above with reference to FIG. 2, gaps 150
are formed by posts or supports 128 extending from ends 126 of
sidewalls 124.
[0036] As illustrated in the embodiment of FIG. 3, printhead
assembly 12' includes compliant material 160' provided within gaps
150. Similar to compliant material 160, compliant material 160' has
a thickness T' substantially equal to or substantially
corresponding to height H of supports 128 such that compliant
material 160' substantially fills and seals depth d of gaps 150. A
length L' of compliant material 160', however, is less than width w
of gaps 150. As such, cavities 170 are formed between supports 128
and compliant material 160' within gaps 150. Compliant material
160', however, similar to compliant material 160, seals gaps 150
thereby preventing bubbles or particles in fluid within fluid
chambers 122 from being trapped in gaps 150 while still allowing
flexible membrane 130 to move or deflect.
[0037] FIG. 4 illustrates another embodiment of printhead assembly
12. In the embodiment of FIG. 4, printhead assembly 12'' includes
substrate 120, flexible membrane 130', and actuators 140. Flexible
membrane 130' is supported at ends 126 of sidewalls 124 such that
gaps 150' are provided between flexible membrane 130' and ends 126
of sidewalls 124. In one embodiment, similar to that illustrated
and described above with reference to FIG. 2, compliant material
160 is provided within gaps 150'. Thus, similar to compliant
material 160 provided within gaps 150, compliant material 160 seals
gaps 150' while still allowing flexible membrane 130' to move or
deflect.
[0038] As illustrated in the embodiment of FIG. 4, gaps 150' are
formed by posts or supports 138 extended from flexible membrane
130'. As such, flexible membrane 130' is supported at ends 126 of
sidewalls 124 by supports 138. Although a single post or support
138 is illustrated as extending from flexible membrane 130' at each
sidewall 124, it is within the scope of the present invention for
one or more posts or supports 138 to extend from flexible membrane
130' at each sidewall 124. In addition, although posts or supports
138 are illustrated as being aligned with a center of a respective
sidewall 124, it is within the scope of the present invention for
posts or supports 138 to be offset from a center of a respective
sidewall 124.
[0039] In one embodiment, supports 138 have a height H' and,
similar to that illustrated and described above with reference to
FIG. 2, gaps 150' have a width w' and a depth d'. In one
embodiment, width w' of gaps 150' is less than width W of sidewalls
24, and depth d' of gaps 150' is equal to or corresponds to height
H' of supports 138. In one embodiment, thickness T of compliant
material 160 is substantially equal to or substantially corresponds
to height H' of supports 138 such that compliant material 160
substantially fills and seals depth d' of gaps 150'. In addition,
length L of compliant material 160 is substantially equal to or
substantially corresponds to width w' of gaps 150' such that
compliant material 160 substantially fills and seals width w' of
gaps 150'.
[0040] Although specific embodiments have been illustrated and
described herein, it will be appreciated by those of ordinary skill
in the art that a variety of alternate and/or equivalent
implementations may be substituted for the specific embodiments
shown and described without departing from the scope of the present
invention. This application is intended to cover any adaptations or
variations of the specific embodiments discussed herein. Therefore,
it is intended that this invention be limited only by the claims
and the equivalents thereof.
* * * * *